deriveSigilDid
abstract suspend fun deriveSigilDid(activity: Activity, passkeyManager: PasskeyManager): SigilDerivation
Convenience one-shot: runs a PRF ceremony with prfSalt, derives the DID, returns it plus the credential ID from the assertion.
Triggers exactly one biometric prompt. Throws whatever PasskeyManager.authenticateWithPrf throws when the ceremony fails (cancellation, RP-id mismatch, missing PRF support, etc.).
Use prfSalt + deriveFromPrfOutput when you're already running a multi-salt ceremony for other reasons (e.g. SigilSession).